13"You are the salt of the earth; but if the salt has lost its saltiness, how can it be made salty again? It is no longer good for anything, except to be thrown out and trampled under foot by men.

 14"You are the light of the world. A city set on a hill cannot be hidden;

 15nor does anyone light a lamp and put it under a basket, but on the lampstand, and it gives light to all who are in the house.

 16"Let your light shine before men in such a way that they may see your good works, and glorify your Father who is in heaven.

What Jesus is saying here, is that people are like salt, and good deeds are saltiness. Salt is necessary to preserve food, but it also makes bad food taste good. If people are salt, living is the salt itself and good deeds are the saltiness. This isn’t to say someone who has not committed good deeds deserves to be trampled underfoot, but just that they aren’t being as helpful as they can. As salt can make bad food taste better, good deeds can brighten someone’s life; kindness is the spice of life.

The verses on “the light of the world” expand upon people and good deeds. People bring light to the world through good acts. It is clear to others when you do good things, as a city upon a hill cannot be hidden. This expands to say that when you have light, you should not be afraid to show it. You should let it glow so that everyone can benefit from it; so it does the most good. All in all, it is up to people to do good things, to help others, and that people should not be afraid to let their good acts show.